Ducted rocket propulsion means for aircraft



April 10, 1951 H. B. GROW DUCTED ROCKET PROPULSION MEANS FOR AIRCRAFT Filed Nov. 17, 1944 INVENTOR. f/41?; 014/ 6 5 ma Patented Apr. 10, i951 UNITED STATES PATENT orrrce AIRCRAF Har1awB'.-Grow, New Carlisle', ohia Application November 17, 1944, Serial-No; 56,976 2 claims: (01. 6045 (Granted. under the; act of amended April 1 30, 1928 The invention described herein may b'e manu-t featured and used by or for the Government .ror governmental purposes, without the paymentto meet any royalty thereon.

This invention relates to jetpropulsion means; andmore particularly to ducted rocket propul+ sionmeans for aircraft.-

In propulsion devices employing the jet pro pulsion principles, one type inuse is commonly knownas the purejet or rocket propulsion type and employs an oxidizer, which together with the fuel, isdeli vered to the burning chamber, burned and dischargedthr'ough the jet tube into the" atmosphere to cause a reactive force inthe direction opposite to thedischarg ed end of the jet tube. 1 This type of jet propulsion is capable-of high? thrust characteristics, especially if operated at maximum e'fiiciency, but'in propulsion devices for use with aircraft, a continued thrust must be maintained over such long time'periods, that pure Jet propulsion motors cannot be operated .at their maximum eii'icienc-y because proper combustion creates so much heat in the combustion .cham her and burner tubes that no materials are avail-:- able, even of the semi-precious types, capable of withstanding-this intense heat and pressureover these prolonged periods of time."

One-method. of operating these purecjet motorssfor aircraft propulsion, in order to prevent too rapid .destruction and "burning out of the apt-- paratus is'touoperate them inefiiciently by ad-- justing the supply of fuel and oxidizing agent SOslEhEtt theocombustion- .in the combustion than;- her incomplete. This inefficient; operation \ree duces the degree of :heat in the combustion cham: her to a point where it can be-.,hand1ed with some degree of success, and a substantial portionof the combustion occurs as it leaves the combusetion chamber and jettubes.

Thermal-air jet propulsion differs -from; the aforementioned pure jet propulsion largely on thebasis of the source of the oxidizer, the .heat generated, and uses atmospheric air as the oxidizing. agent while pure jet propulsion apparatus supplies-its own oxygen, In the thermalejet motor the air isintroducedth-rough a restricted or ram jet opening at a relatively-high velocity in the front end of a ram jet casing,known1 as an .athodyd or aerothermal dynamicpody-having a somewhat streamlined, enlarged, central body portion tapering to a restrictedodischargeopen ing or jet discharge passage at-the other end. The velocity of the air enteringtheenlarged chamber i's reduced and theair'isdynam'ically March 3, 1883, as 370 O. G- 757) compressed, after which intense heat is applied to theair, causing its expansion and discharge through the restricted discharge passageat a high velocity. This produces a forward'thrust on the body in the direction away from the discharge jet opening or duct.

Pure jet apparatus,- carrying its own oxidizer is light in Weight, has no moving parts; and can function independently of the atmosphere, but its operating efiiciency, as mentioned before, must be necessarily 10w and not tolerable inpractice asla main propulsion device for aircraft.

An object of the present invention is the-provision of an improved aircraft propulsion device, employing ac'ombinedthermal and pure jet or rocket propulsion apparatus.

A further object is the-provision of a combined thermal-air and pure jet propulsion motorzinuwhich the pure jet principle is employed within .a thermal air j et propulsion device to in crease the efliciency of the apparatus.

A ,still further object of the invention is the proyision .of apparatus which eliminates the usual moving parts employed in the conventional ther maleair jetupropnlsion motor and increases the efficiency 01 jthe device byemploying pure jetzpropulsionmeansrwi-thiiijthe thermal-air jet motor for'supplyingthethermal efiiciencyto the air i-ne troduced into the;apparatus andreffecting compressionof the air prior to its heating and dis charge, I v

A-stil l further obj ect-is the provisionof a; combined thermal-air jet and pure jet propulsion means in which; the efliciency lost ,in the pure jet motor is util izedqto eiiect a more veiiicient ope eration of the .thermal-air jet portion ofthe propulsionmeans. A 7

Other objects and advantages-of the invention will become apparent.fromthefoIlOWing description,,taken in conneetionwith the accompanying'drawing, iii-which likeereference characters refefto l ik'e parts" in the several figures.

Drawing" .Fig: is an enlarged longitudinal sectionalyie'vv taken through my improved .ai'rcraft ropulsion motor. p i

Fig, 2 is a cross-esect'ional view takenjapproxirnate'lyon theiplanje' indicated by line z zin Fig.1.

Fig; 3 isan enlarged detailed view of one of the pure jet or rocket *n'iotors" emp1oyed=-byme and loated Within the tliermo air jet propulsion Inotor.'-

g.4: is an" end view or the jet unitshown in Fig. 5 is an enlarged sectional view of the modified form of my invention.

Fig. 6 is a cross-sectional view taken on 6-6 of Fig. 5.

Fig. 7 is a further modification; and

Fig. 8 is a sectional view taken on line 8-8 of Fig.7.

Referring more particularly to Figure l of the drawing, the reference numeral I indicates generally a casing or ram jet body of the thermalair jet propulsion design, having an air admission port or ram jet opening 2 at the front end thereof and a jet discharge or duct 3 at the opposite or rear end portion. The portion of the body I intermediate the ramjet inlet and discharge ports 2 and 3 is streamlined to form an enlarged intermediate air compression and heating chamber 4.

Located within the body between the air inlet port 2 and the enlarged air compression chamber 4 are a plurality of pure jet propulsion devices or rocket motors 5, each having their discharge opening 6 facing the jet discharge opening 3 of the body.

The pure jet propulsion motors 5 are integrally supported from the side wall of the chamber 4 by suitable supports or brace members 1 so as to communicate the forward thrust of these pure jet motors 5 to the body when they are in operation within the body.

Fuel and a suitable oxidizer are supplied to the pure jet motor 5 in the usual manner, conduits 8 and 9 forming suitable fuel and oxidizer medium supply means from the supply tanks l and II, suitably carried on the aircraft or vehicle structure to be propelled (not shown) which carries the ram jet body.

In this form of invention, when the pure jet motors are in operation and the vehicle or aircraft carrying the ram jet body I is moving forward at the desired velocity, air enters the restricted ram jet inlet 2, passes into the enlarged portion of the streamlined compression chamber 4. As the air moves toward the larger portion of the interior of the chamber, it loses some of its velocity and its mass pressure is increased. The incoming air through the inlet opening or mouth 2 causes the air to be compressed dynamically or rammed in the space just to the rear of the pure jet motors 5. The jets from these pure jet motors produce an intense blast of heat which is projected rearwardly through the compression chamber toward the discharge end 3, this induces a flow of air around the jets, and the heat from the pure jets is transferred to the air in the compression chamber 4, tending to increase the pressure of the air against the walls of the chamber with a resulting increase in velocity through the discharge end.

Since these pure jet motors are usually and necessarily operated with a considerable amount of the combustion taking place within the athodyd body in the rear of the jets this intense heat and blast effectively heats and expands the incoming air in the combustion chamber and the reactive or forward thrust of the pure jet motor 5, and the forward thrust of the thermal-air jet arrangement of the ram jet body are accumulative to provide a high total forward thrust on the vehicle or aircraft on which my improved propulsion motor is mounted.

The apparatus is light in weight since the usual power operative compressor ordinarily employed and its motors are eliminated. The pure jet motors may be operated successfully within the ram jet body since any combustion taking place at or outside of the pure jet discharge ducts is not wasted as when pure jet motors alone are employed, but is utilized to heat the air within the body to obtain the desired expansion thereof in the chamber 4. The exchange of heat between the pure jet propulsion devices and the air passing the bodies of these devices tends to increase the thermal efiiciency of the air, and helps to maintain the pure jet propulsion members cooled to below their destructive temperatures.

In the event that the heat transfer from the pure jet motor body and from the pure jet discharge is not sufficient to heat the air that is compressed in the heating and compression chamber 4, each pure jet motor 5 may be provided with supplemental heating means, indicated generally at 14 in the drawings.

Referring more particularly to Figs. 3 and 4, disclosing enlarged views of the jet motor 5, this auxiliary air-heating means may be in the form of an annular chamber I3, in a peripheral flange projecting laterally from the discharge end of the pure jet motors. This flange is provided with a plurality of burner apertures l2. Fuel for these burners I2 is supplied to the annular chamber l3 in any suitable or well-known manner, such as by the fuel-delivered conduits IS. The heat supplied to the air in the thermal air or ram jet compression chamber 4 by these supplemental burners l2, and the heat exchange between the pure jet propulsion devices 5 and the air is sufficient to maintain my improved combined pure and thermal-air means operating at a maximum thrust efficiency.

Referring to the modified form of the invention, as disclosed in Fig. 5, the body of the ram jet casing is similar in shape to the form shown in the Figs. 1 and 2 and is provided with an airintake port 2a at the front end and a discharge duct 3a. at its rear or opposite end. The enlarged intermediate portion of the ram jet casing, indicated at fla is cylindrical for a portion of its length, and has slidably mounted within the cylindrical portion a partition ll.

The partition I! has formed therein a plurality of the aspirator or funnel-shaped openings l8 adapted to axially register with pure jet propulsion motors 5a carried by the ram jet casing or body, on fixed supports la. These motors 5a are supplied with fuel and a suitable oxidizing agent in the same manner as the pure jet motors disclosed in Fig. 1. Provision is made for adjusting the longitudinal position of the partition H carrying the funnel-shaped openings or aspirator ports [8 with respect to the pure jet motors. The body is preferably slotted longitudinally at opposite sides to receive arms I9 projecting from the partition member l1. These arms l9 may be connected to any suitable adjusting means such as rods 20, carried on pistons, located within the hydraulic cylinders 2| which are secured on the exterior on the body I. Pressure may be applied to either end of the cylinders 2| to shift the partition member I! to vary the position of the aspirator openings with respect to the jets from the pure jet motors 5a.

In the operation of this form of invention, air passes into the body through the restricted inlet port 2a, around the pure jet motors 5a. The blast from the pure jet motors passing through the aspirator openings in the partition member l8, causes the air in the forward portion of the body to be forced into the rear portion or compression end of the heating chamber 4a and the g with heat transfer to the air in the compression chamber from the pure jet discharge and from the causes the expansion and discharge of the air from the body and the forward thrust to the body.

Referring to the modified form of my, invention, disclosed in Figs. 7 and 8, the body lb is provided, in the forward portion of the enlarged compression and heating chamber 96, with a plurality of concentric rearwardly-tapering aspirator tubes or funnels 22, rigidly supported from the interior Wall of the body. A pure jet propulsion motor or device 51) is securely mounted by fixed supports lb in the body in advance of the aspirator funnels 22, so that the jet therefrom passes centrally through the funnels into the compression and heating chamber 4b.

Air entering the air inlet opening 21) in the forward end of the body is packed or rammed into the expansion and compression chamber 417 due to the aspirator action of the pure jet passing through the funnels 22, and is heated. The pure jet blast provides the necessary thermal energy for the thermal-air jet and the thrust of the pure jet propulsion device 5a together with the thrust of the thermal-air jet portion of the body effects a maximum thrust with a minimum loss in energy and efiiciency.

Having described my invention in connection various changes may be made in the shape, size, and arrangement of the parts without departing from the spirit of the invention as defined by the appended claims.

I claim:

1. In a combined thermal air jet and pure jet propulsion motor of the class described, a ram jet body having an air inlet port at its front end, a thermal jet propulsion and thermal air jet propulsion devices, utilizing the heat from the pure jet propulsion device to compress, heat and expand the with an enlarged intermediate air compression heating chamber, a pure jet propulsion motor device located within the enlarged air comprespure jet opening. for supplying supplemental heat to the air within the enlarged heating chamber of the body surrounding the pure jet discharge from the pure jet propulsion device.

HARLOW B. GROW.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 784,488 Googins Mar. 7, 1905 1,103,503 Goddard July 14, 1914 1,167,139 Williams Jan. 4, 1916 1,369,672 Koenig Feb. 22, 1921 1,375,601 Morize Apr. 19, 1921 1,389,797 Thompson Sept. 6, 1921 2,396,911 Anxionnaz Mar. 19, 1946 FOREIGN PATENTS Number Country Date 484,405 Great Britain May 2, 1938 798,489 France Mar. 10, 1936 818,703 France June 21, 1937 330,905 Italy 'Oct. 26, 1935 612,362 Germany Apr. 18, 1935 

